1. Field of the Invention
The present invention relates generally to medical devices for reduction, stabilization, and fixation of bone fractures, and more particularly to an articulated fracture fixation device with an adjustable modulus of rigidity, or elasticity in shear.
2. Discussion of Related Art Including Information Disclosed Under 37 CFR 1.97, 1.98
Intramedullary nailing of fractures was developed by Gerhard Kuntscher in Germany in the early 1940's. In the ensuing decades, this technique has come to be accepted as standard treatment for a middle-third shaft fracture of a long bone in the human body. While any long bone can be indicated for treatment with an intramedullary device, the most common application for this technique is in the femur and in the tibia.
While many different devices have been developed and utilized over the years, the technique has changed little. The procedure requires that the medullary canal of the bone be opened at either end of the bone. A guide rod is then placed lengthwise through the canal and across the fracture site while the fracture is reduced (the bone fragments returned to anatomical position). The medullary canal is then prepared for the implant, most commonly by systematically reaming in steps over and along a portion of the length of the guide rod. Once the canal is prepared, a properly sized implant is selected and installed over the guide rod, thereby effecting stabilization of the fracture. The guide rod is then removed and the surgical approach site is closed. The patient can begin rehabilitation shortly thereafter, and much sooner than had the fracture been fixed by earlier means, such as traction or a plaster cast.
In its essential form, an intramedullary nail is nothing more than a stabilization device that functions as a kind of internal splint. More elaborate devices have allowed for rotational stabilization and for proximal and distal fixation with varying degrees of success and utility.
However, all of the devices to date are poorly matched to the human anatomy. While an average curvature of the long bones can be applied to the manufacture of an array of implants to approximate the anatomy of most of the population, it is impossible to ensure that any implant will be absolutely correct in any given application.
Accordingly, an improved intramedullary device to reduce, stabilize, and fix fractures is needed, one, specifically, that may be tailored in size and shape to the particular patient and the particular conditions of the fracture and bone configuration encountered by the surgical team.
Improvements to the customary approach to fracture fixation have been proposed and are disclosed and discussed in the following exemplary patents.
U.S. Pat. No. 6,755,862, to Keynan, discloses an intramedullary support strut for a long bone for anchoring and fixation. The strut comprises nested telescopic members having retraced and extended configurations. In the retracted configuration, the strut is compact and may be inserted into position aligned with a shaft made in the medullary canal via a portal made in the lateral cortex of the bone. The strut may then be telescopically extended into the medullary canal to provide the required support.
U.S. Pat. No. 5,997,582, to Weiss, discusses the use of an expandable balloon to stabilize and fix a femoral head after hip replacement surgery.
U.S. Pat. No. 5,645,545, to Bryant, shows a self-reaming intramedullary nail that includes a rotatable reaming head mounted to the distal end of the cannulated nail body. A detachable drive shaft connects reaming head through nail body to a conventional rotational drill device. Reaming head and drive shaft have longitudinal bores that when connected form a passage for receiving a guide wire.
U.S. Pat. No. 4,190,044, to Wood, teaches a telescoping Intramedullary pin having a main body or base which is inserted in a drilled out marrow cavity of one-half of the broken bone. A portion of the marrow of the cooperating half of the broken bone is drilled out to accept the telescoping plunger which is positioned in the base. The two halves of the bone are brought together and the telescopic plunger is forced from the base into the drilled out marrow cavity by a stainless steel wire which is connected to the bottom of the telescoping pin and extends out of the bone cavity through the fracture. When the plunger is extended to its desired length, the stainless steel wire is cut and removed from the bone. The telescoping plunger is prevented from returning to the interior of the base by a series of ridges spaced longitudinally along the body of the plunger, which cooperate with faces of the resilient side walls of the base to prevent the reinsertion of the plunger into the base by providing an obstacle against which the ridges abut when return force is applied to the plunger.
U.S. Pat. No. 6,120,504, to Brumback, et al, discloses an intramedullary nail having a longitudinal centerline extending between a distal end and a proximal end. The nail defines a proximal attachment orientation adjacent the proximal end. The nail also defines a left distal bore and a right distal bore adjacent the distal end. The left distal bore and the right distal bore are anteverted in different directions about the longitudinal centerline with respect to the proximal attachment orientation. Thus the same nail can be used in an interlocking, reconstructive or retrograde fashion.
The foregoing patents and other prior art reflect the current state of the art of which the present inventor is aware. Reference to, and discussion of, these patents is intended to aid in discharging Applicant's acknowledged duty of candor in disclosing information that may be relevant to the examination of claims to the present invention. However, it is respectfully submitted that none of the above-indicated patents disclose, teach, suggest, show, or otherwise render obvious, either singly or when considered in combination, the invention described and claimed herein.